JP4439399B2 - Method - Google Patents

Abstract

A method of reducing wear in a cutting head of a tunnel boring machine, by means of the addition at the cutting head of a foamed aqueous liquid composition, which comprises a foaming agent and a lubricant, the lubricant being selected from the group consisting of high molecular weight polyethylene oxides and bentonite. Preferred foaming agents are anionic and nonionic surfactants. Wear rates of cutting elements of TBMs boring in hard rock are considerably reduced. A wear-reducing foamable concentrate is also described.

Description

Detailed Description of the Invention

  The present invention relates to a method of tunnel excavation of hard rock and a composition used for the excavation.

  Drilling in hard rock tunnels such as limestone and metamorphic or igneous rocks always has more problems than drilling softer rocks. The most commonly used method for tunneling such rocks was to drill a blasted hole after exploding with gunpowder. For tunnels with hard rocks, it has been desired to use tunneling machines (TBMs), which are machines with large diameter cutting heads (sometimes over 10 m). The main problem with TBMs used for such rocks is the disadvantages of both the need for rapid wear and frequent replacement of the cutting element (hard steel disc protruding from the cutting top), operability and economy. .

  It has now been found that the use of a special composition can significantly reduce this wear and make the drilling of TBM hard rock more efficient and economical. Accordingly, the present invention tunnels by adding a foamed water-soluble liquid composition to the top of the cutting comprising a blowing agent and a lubricating oil, wherein the lubricating oil is selected from the group consisting of high molecular weight polyethylene oxide and bentonite. A method is provided for reducing wear on the cutting top of a machine.

  The foaming agent may be any foaming agent, and may be any material that forms a stable foam when stirred in water. Two or more such foaming agents can be used in the composition used in the present invention. A wide variety of such materials are known in the art. A preferred material for use as the foaming agent of the present invention is a surfactant, a material having both hydrophilic and hydrophobic sites. Although any suitable surfactant can be used, for the purposes of the present invention, the surfactants that work best are anionic or non-ionic, which have been found to be preferred surfactants. .

  When the surfactant is an anionic type, a sulfate-containing surfactant is preferred, more preferably alcohol sulfuric acid and most preferably lauryl sulfuric acid. Many suitable materials are known in the art, and an example of a particularly preferred material is monoisopropanolamine lauryl sulfate (eg, commercially available under the trade name “Sulfetal” Cjot 60).

  When the performance of anionic surfactants is good, their use may be undesirable when the environment is important. For the environment, it is preferable that the foam is short-lived, that is, the foam is in a foamed state only while the foamed liquid is generated and removed from the cutting surface. Anionic surfactant foam may be found in rivers far from the site because it is stable and long-lasting. In such cases, nonionic surfactants are preferred, and their performance in the field is no less good, but biodegrades faster and any bubbles that are generated are relatively short lived. In addition, the degradation components of nonionic surfactants are significantly less harmful than those of anions, and therefore less risk of harm to plant and animal ecology.

Examples of effective nonionic surfactants suitable for use in the present invention are alkanolamides, aminoxides, ethoxylate alcohols, ethoxylate alkylphenols, ethoxylate esters, glucose and sucrose esters and derivatives thereof. Glucose and sucrose esters and their derivatives are particularly effective, especially alkylpolyglucosides. Among these, a commercially available example is “Lutensol ™” GD 70 (
For example, BASF) and “Glucopon ™” (eg, Cognis).

  The lubricating oil can be selected from one of two different materials that are already commercially available. “High molecular weight” polyethylene oxide (PEO) means PEO having an average molecular weight of at least 1,000,000. Preferably, the molecular weight is 2,000,000 to 8,000,000. Such materials have been used previously for tunneling TBMs, but were never associated with hard rock excavation. Commonly commercially available materials include POLYOX® WSR-301. Since PEO is a polymer, it has a molecular weight distribution and is therefore essentially a mixture of different materials, but a mixture of different PEOs may be used.

  An alternative lubricant is bentonite. This clay material is already well known as a component of boring mud and has also been used in some TBM applications. However, the use associated with blowing agents to achieve this particular purpose described above is new. Although any commercially available bentonite is suitable for the purposes of the present invention, a common example is “Tixoton” ™.

  The composition is prepared by adding an appropriate amount of water for use. The supply of a dry composition is theoretically possible and not excluded from the present invention, but not possible. The reason for this is the work of creating a liquid composition in the field, which is particularly difficult with high molecular weight PEO, which is water soluble but difficult to dissolve. In addition, other commercially available additives (described further below) are often supplied only in the form of solutions or suspensions.

  There are two ways to overcome these problems. First, the composition is supplied as a series of individual water-soluble ingredients that are metered in a precise individual ratio into a relatively large amount of water for foaming. Accordingly, the PEO and / or bentonite, the foaming agent, and any optional components (further described below) are each provided in a water-soluble form. The required containment and weighing-in devices are well known in the art and need not be described further here. This method has the advantage of versatility, the amount of ingredients can be varied to suit when a local situation occurs, and can optionally contain any optional ingredients. It is even possible to include both types of lubricants (PEO and bentonite), and they can be interchanged. Of course, there are disadvantages in that additional equipment components are introduced, along with associated cost and maintenance issues.

  A more desirable method for most applications is to provide a concentrate, aqueous solution or suspension having the necessary components in the appropriate ratios, which can be used quickly and conveniently. There is no problem of diluting such concentrate on site and foaming the diluted concentrate. Where the versatility of the weighing method already described is not necessary, this method is preferred because of its ease of use and relatively low cost.

  The amounts of the ingredients described in the following paragraphs are sufficient to provide the dry ingredients and sufficient to make the individual ingredients water-soluble for the individual weighings described above or for the preparation of the water-soluble concentrates described above. The present invention relates to a water-soluble composition containing water. The composition is made up to 100% with water. This does not include the final dilution and foaming water (see [0019] for the amount).

When using PEO as a lubricating oil, the amount of PEO to be used is 0.1 to 3.0%, preferably 0.4 to 2.0%, more preferably 0.5 to 0% by weight of the concentrate. 1.0. The amount of corresponding blowing agent is 2-40%, preferably 5-30%, more preferably 5-20%.
When bentonite is used as the lubricating oil, the amount is 2 to 30%, preferably 2 to 25%, more preferably 2 to 20%, and the amount of the corresponding blowing agent is 2 to 40%, Preferably it is 4 to 20%, More preferably, it is 5 to 15%.

  Other components can also be added to the composition used in the present invention. Two particularly useful components are sequestering agents and foam boosters. These are usually more effective in the composition when PEO is a lubricating oil, but can also be used in bentonite. In more preferred cases, anionic surfactants are more effective and non-ionic surfactants have little effect. This is especially true for sequestering agents.

  Sequestrants exist to counter the problems caused by the use of hard water used to prepare the final foaming solution. Hard water can lead to precipitation of the blowing agent, making the composition useless. Of course, when no hard water is present, sequestering agents are not necessary, but the addition of such materials provides a composition that can be used in any water state and for use in any environment. Always respond. Any suitable sequestering agent can be used, and the amount used is 5% or less, preferably 0.1-5%, more preferably 0.5-2%, most preferably 1-1.5. %. An example of a sequestering agent suitable for use in the present invention is “Cublen” ™ K2523.

  The foam booster can be any suitable material as well. The amount to be used is 10% or less, preferably 0.1 to 10%, more preferably 0.1 to 1%. An example of a foam booster suitable for use in the present invention is “Aromox” ™ MCD-W.

The present invention also provides a wear-reducing foam liquid concentrate, comprising at least one lubricating oil selected from high molecular weight polyethylene oxide and bentonite and at least one blowing agent that produces short-lived foam, optionally at least one It also contains a sequestering agent and at least one foam booster, each abundance relative to the weight of the concentrate:
(A) In the case of polyethylene oxide as the lubricating oil,
0.1-3% polyethylene oxide;
2-40% blowing agent;
5% or less sequestering agent;
1% or less foam booster;
And (b) in the case of bentonite as a lubricant,
2-30% bentonite; and 2-40% blowing agent;
And the rest is water.

In use, in the case of a concentrate, the appropriate amount of water is added to the concentrate and foamed before it is fed to the top of the rotary cutting and poured into the cutting top and rock interface. In the case of an individual component weighing system, the desired amount of water-soluble component is weighed and foamed with an appropriate amount of water. In general, the concentrate / individual components described above are diluted with water and the concentrate / individual component is 1-20%, preferably 1-10%, more preferably 1-8% and most preferably A water-soluble composition having 1 to 6% is obtained.
This diluted composition is foamed by any convenient method and is 5 to 40 times, preferably 5 to 20 times, more preferably 8 to 20 times the volume of the non-foamed material.

The actual dilution and foaming amount of the concentrate / individual component will vary considerably depending on the specific environment. Factors such as cutting top diameter, number and location of injection nozzles and rock properties are the main effects. An essential requirement is to maintain a foam layer in contact with the rock surface over the entire area of the cutting top. Achieving this requirement is a routine experiment and can be easily performed by those skilled in the art. Common quantities of the above types of concentrates, rocks 1 m ³ per removing a concentrate 0.5～10.0Kg rock 1 m ³ per preferably removed, concentrate 0.5~6.0kg More preferably, it is 1 to ⁴ kg of concentrate per 1 m ^{3 of} rock to be removed. When adding individual water-soluble ingredients, the corresponding amounts can be easily calculated. It is emphasized that these quantities are given only as general guidelines and that low or high amounts of individual components or concentrates are required depending on established conditions.

  The use of the water-soluble liquid composition described above significantly reduces the wear of hard rock cutting elements, reduces the longer life and frequent replacement of the cutting top, and results in a better and more economical tunneling. Without limiting the scope of the invention in any way, it is believed that the fine materials created on the drilling surface of the TBM will bind together by the water soluble liquid composition and act as a lubricant.

The invention will now be illustrated by the following non-limiting examples.
Composition A (using an anionic surfactant)
The following ingredients are used:

Compositions B and C (with nonionic surfactant)
The composition is:

In order to save measurement time and money, a method for ascertaining the effectiveness of the composition used in the present invention before use in the TBM requires the following equipment. :
PVC wide mouth bottle, 1 liter, wide mouth specimen silicon carbide powder (0.841-1.19mm)
The specimen consists of three wheels of ST50 steel with a diameter of 50 mm, a thickness of 14 mm and an axial hole of 10 mm in diameter, three fixed to the M10 bolt by any suitable means (nuts and washers etc.). There is a space of about 14 mm between adjacent wheels.

The procedure is as follows. :
400 g of silicon carbide is mixed with a quantity of water and composition and added to the jar. The weights of the three individual wheels are known exactly (0.001 g), the specimen is added to the jar, the jar is sealed, placed on the mill and rotated at 125 rpm for 3 hours. . The wheels are then surveyed to reduce weight (wear).

  Compositions A, B and C are measured in this way. In either case, the composition is diluted with water (5% composition in water) and the 30 and 60 g samples are foamed to 10-fold volume expansion. Under control, 60 g of water is added to a 400 g sample of silicon carbide and measured. The wear rate of the test piece is as follows. :

  It can be seen that the wear rate is significantly reduced in some cases.

Claims (5)

A method for reducing wear on a cutting top of a tunnel excavator by adding a foamed water-soluble liquid composition to the cutting top, comprising a blowing agent and a lubricating oil, wherein the blowing agent is an alkanolamide, an aminoxide, an ethoxylate A nonionic surfactant selected from the group consisting of alcohols, ethoxylate alkylphenols, ethoxylate esters, glucose and sucrose esters and derivatives thereof , wherein the lubricating oil is selected from the group consisting of high molecular weight polyethylene oxide and bentonite. Said method.   The method of claim 1, wherein individual components of the foam composition are metered into water in individual water-soluble forms and converted to foam.   The method of claim 1, wherein the composition is supplied as a concentrate and diluted in situ with water to provide a foamed composition. At least one lubricating oil selected from high molecular weight polyethylene oxide and bentonite , and non-selected from the group consisting of alkanolamides, aminoxides, ethoxylate alcohols, ethoxylate alkylphenols, ethoxylate esters, glucose and sucrose esters and derivatives thereof An ionic surfactant comprising at least one blowing agent that produces a short-lived foam, optionally also comprising at least one sequestering agent and at least one foaming booster, each present in a liquid composition For the weight of:
(A) In the case of polyethylene oxide as the lubricating oil,
0.1-3% polyethylene oxide;
2-40% blowing agent;
5% or less sequestering agent; and 1% or less foam booster;
And (b) in the case of bentonite as a lubricant,
2-30% bentonite; and 2-40% blowing agent;
Abrasion-reducing foam liquid concentrate that is and the rest is water.   The wear-reducing foamed liquid comprising the concentrate according to claim 4, which is diluted with 1 to 20 volumes of water and foamed to expand volume by 5 to 40 times.